SEMICONDUCTOR MEMORY DEVICE AND MANUFACTURING METHOD OF SEMICONDUCTOR MEMORY DEVICE

摘要

A memory includes active areas and an isolation on a semiconductor substrate. A tunnel dielectric film is on active areas. Floating gates include lower gate parts and upper gate parts. An upper gate part has a larger width than that of a lower gate part on a cross section perpendicular to an extension direction of an active area, and is provided on the lower gate part. An intermediate dielectric film is on an upper surface and a side surface of each floating gate. The control gate is on an upper surface and a side surface of each floating gate via the intermediate dielectric film. A height of a lower end of each control gate from a surface of the semiconductor substrate is lower than a height of an interface between the upper gate part and the lower gate part from the surface of the semiconductor substrate.